Dr Jack
Member (Idle past 303 days) Posts: 3507 From: Leicester, England Joined: 07-14-2003
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Message 17 of 18 (817985)
08-22-2017 11:31 AM
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Reply to: Message 1 by Taq
07-19-2017 4:48 PM
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Nature blog casts doubts
A Nature blog post critical of the study. Their objections are different to mine but I agree with them too.
| This message is a reply to: | | | Message 1 by Taq, posted 07-19-2017 4:48 PM | | Taq has responded |
| Replies to this message: | | | Message 18 by Taq, posted 08-23-2017 1:00 PM | | Dr Jack has acknowledged this reply |
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Taq
Member Posts: 7971 Joined: 03-06-2009 Member Rating: 4.5
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Message 18 of 18 (818095)
08-23-2017 1:00 PM
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Reply to: Message 17 by Dr Jack
08-22-2017 11:31 AM
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Re: Nature blog casts doubts
| Dr Jack writes: A Nature blog post critical of the study. Their objections are different to mine but I agree with them too. |
I agree with most of them, too. There is no way around the fact that the lac promoter is leaky, so you will always get some expression. This will bias your results, even in the absence of induction with IPTG. Even after a few generations, their library will be skewed away from lethal and neutral mutations and towards slightly beneficial and beneficial mutations. That selection will be skewed once again when you have strong over-expression with IPTG. One could also easily argue that a specific gene is slightly beneficial with low expression, but deleterious with high expression. This may be why they see stable variation with no induction, but changes after induction. Either way, they seem to have found beneficial genes among random sequences. The real question is how common are they?
| This message is a reply to: | | | Message 17 by Dr Jack, posted 08-22-2017 11:31 AM | | Dr Jack has acknowledged this reply |
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